FIGURE 1.

The glucan phosphatase active site. A, multiple sequence alignment of the PTP-loop from At-SEX4-(198–204), At-LSF2-(193–199), Hs-laforin-(266–272), At-LSF1-(390–396), and Hs-VHR-(124–130). The catalytic cysteine and arginine are colored red and blue, respectively. The Gly residue strictly conserved in all PTPs is colored dark gray, and residues conserved in glucan phosphatases are colored light gray. Numbers refer to the amino acid position carboxy-terminal to the catalytic cysteine. B, interactions between the PTP-loop (yellow) and glucan chain (green) in SEX4 (PDB code: 4PYH), LSF2 (PDB code: 4KYR), and laforin (PDB code: 4RKK). The catalytic cysteine (C) is colored red and the phosphate orange. The numbers highlight the residues outlined in the multiple sequence alignment shown in panel A.